With the development of electronic cigarettes, various electronic cigarettes with different structures have been invented. Among these electronic cigarettes, a cotton-free electronic cigarette is a highly popular electronic cigarette right now. The cotton-free electronic cigarette has fewer components than conventional electronic cigarettes, so the assembly of the components of the cotton-free electronic cigarette is easy and the assembled cotton-free electronic cigarette has a simple structure. The cotton-free electronic cigarette uses a liquid percolation piece to directly absorb cigarette liquid stored in a liquid storage cup, so the way of fixing the liquid percolation piece and the liquid storage cup is significant to the prevention of liquid leakage and to the smooth supply of cigarette liquid.